1. Field of the Invention
The present invention relates to a method for replacement arthroplasty to prepare an artificial joint by use of an ultrasonic treatment device.
2. Description of the Related Art
In general, an artificial joint wears away and loosens due to long use. When this looseness is generated, a replacement operation is required again. However, when a user is very old, the user might hesitate to undergo the operation again in consideration of rehabilitation and the like.
In a case where this artificial joint is, for example, an artificial hip joint, a stem is disposed in a femur. In this case, the femur is cut into a shape to receive the stem (a material of the stem is usually a metal material such as a titanium alloy) with a drill or the like, but in this technique, accuracy of a cut surface is not much high. In a case where the accuracy is low, a clearance is present between the stem and the bone when the stem is attached, and hence friction is generated together with the looseness. Due to this friction, wear debris of the material might be generated. A situation (called bone absorption) occurs in which the worn material is recognised as a foreign matter on a biological side to cause a biological reaction, thereby melting the bone around the artificial joint, and it is considered that this situation increases the clearance around the stem of the artificial joint.
To eliminate such a problem, there is provided a technique to dispose an artificial joint that is hard to loosen even when the artificial joint is used for a long period of time. Furthermore, the technique can contribute to decrease of occurrence of pain, because the artificial joint less loosens.